Top row: CMD of our APOGEE training set across the Gaia, 2MASS, and WISE photometric systems utilized in this work along with the addition of the Gaia+2MASS combination chosen as a feature in our regression analysis. The bulk of the stars lie in the upper RGB with few AGB stars present. Middle row: the color scheme here shows the mean metallicity in each pixel. Gradients are clear across all colors, especially so in WISE owing to its near-vertical RGB. Bottom row: scatter plots between each of our four chosen features and APOGEE metallicity are shown. Positive correlations are evident with the WISE band showing the tightest relation.